A large in-bore transmit body coil and a separate receive coil array has been used for clinical whole body MR scanners. At high and ultra-high field (e.g., greater that 3T strengths), this concept is not well-suited for cardiac and abdominal imaging.
Radio frequency (RF) radiation effects are increasing with frequency and inner bore diameter, which makes the application of standard RF body coils less favorable for high and ultra-high field MR whole body imaging. The B1 homogeneity inside the object no longer depends on the geometry of the coil, but rather is dominated by dielectric resonance and RF eddy current effects. These inhomogeneous effects can be altered and externally modulated by individual current and phase distribution or the application of 3D transmit pulses using transmit sensitivity encoding (SENSE) or other parallel imaging techniques, but such methods are limited by the high specific energy absorption rate (SAR) when using bore-integrated large body coil arrays. The SAR problem can be reduced when focusing on dedicated applications (head, cardiac, abdomen, etc.) using local transmit/receive (T/R) arrays.
Local T/R arrays are more optimal for transmit SENSE applications, as the matrix inversion is better conditioned. Conventional surface coils arrays with single individual coil elements cannot be optimized at the same time for low SAR and high SNR. The present application provides new and improved coil array construction systems and methods, which overcome the above-referenced problems and others.